We have this Ingersoll Rand Lightsource light tower that we use solely as a generator. Uses a Kubota D905 engine and is supposed to be able to put out 6KW. Issue is at the 110V outlet. Things don't run so well plugged into the outlet. For example a grinder spins really slow or a heat gun doesn't get that hot or spin the fan as fast as if it was plugged into the wall. This light tower has no lights on it only running it for the 110V and 220V outlets. My thought is that I could put a volt meter in the 110V outlet and increase the RPM on the engine until I see 110V. The reason I haven't done that is because I had heard the outlets may have a capacitor attached to them that could go bad? I knew the lights had capacitors and I believe those are still on the machine but I didn't know the outlets use a capacitor as well. Is this correct and should I start by checking the capacitor (and where is it located)?
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Low Voltage at Light Tower Outlet
- Thread starter Parts
- Start date
MarshallPowerGen
Senior Member
- Joined
- Nov 26, 2017
- Messages
- 449
- Location
- Northwestern USA
- Occupation
- Generator Technician & Equipment Mechanic
Light towers will be a cap regulated alternator; Should be a cover on top of the gen end that will have the cap. Will need to check the uF rating on the cap versus the actual reading with a meter.
As always thanks for the help. I can do that. Will look around on the generator end for the capacitor. I know where the light tower parts are located but haven't dug into the generator end yet.
Birken Vogt
Charter Member
The thing needs to run at 1800 RPM nominal or maybe 1900 max. If it is not running at the correct speed do not do anything else until it is. Then measure voltage at the source both unloaded and loaded. And again at the equipment in case it is just a wiring problem or something.
I don't have any reason to believe the RPM has been touched from where it was set. It has 6000 hours but I don't know that anyone has touched the RPM. I will take a look at the capacitor first. If that checks out we're gonna adjust RPM until I get 110V
I believe the cap is 22.5uF. Can I replace that just as a matter of course since its been running for 6000+ hours since 1999? Can I match up the exterior size of the current one to find a replacement or does it have to be that exact part number from Ingersoll/Doosan?
1693TA
Senior Member
You need to check engine RPM first. This is the same setup many truck APU's utilize for making 120VAC. Low engine RPM = low output VAC.
Usually the capacitors in this type system don't degrade in value but rather blow the end out, or open internally which eliminates output till it's replaced.
Usually the capacitors in this type system don't degrade in value but rather blow the end out, or open internally which eliminates output till it's replaced.
Good to know. I definitely have output so I guess it could be RPM. I have no way of testing RPM other than raising it until I get 110V at the outlet.
1693TA
Senior Member
Some multimeters have a frequency setting/selection on them. Easy to measure and if you are close to 60cps/hz, you are very close to 1800rpm.
Birken Vogt
Charter Member
If you have a Fluke meter, Hz is the way to go. If you have an off-brand, they are usually totally useless for Hz. Buy a Fluke if your meter gives strange readings. 62-63 Hz unloaded is usually best so it lugs its way into 60 Hz. It has to always run 60-63 Hz no ifs ands or buts. If voltage is still low then fix the electrical problem, don't change engine speed (which is directly locked to Hz reading).
I will check for Hz tomorrow and if we're at 1800RPM 60Hz I'll report back. Curious what the next thing to look at would be if the RPM/Hz is correct?
Birken Vogt
Charter Member
Take out the capacitor(s) and check, most good voltmeters have a capacitor check function.
Ok so here is what we have. The hertz comes in right at 61. The voltage was around 70 or 80. So low voltage but correct Hz. Time to pull the capacitor. I haven't removed a capacitor to test before. Do I first short out the poles with an insulated screwdriver? Then pull it and test resistance or capacitance? My meter can test for capacitance but I haven't done that before so any detailed instructions would be appreciated.
mekanik
Senior Member
Here is a video on testing caps:
There are other ways to test them using a charging voltage through a resistor and
measuring how long it takes to reach 63.2% of the charging voltage.
The capacitance should be marked on the capacitor.
You don't need a Fluke meter. Any quality multimeter should work.
There are other ways to test them using a charging voltage through a resistor and
measuring how long it takes to reach 63.2% of the charging voltage.
The capacitance should be marked on the capacitor.
You don't need a Fluke meter. Any quality multimeter should work.
mekanik
Senior Member
I would test it first. Do you have the manual for the unit?
mekanik
Senior Member
it will have a voltage regulator and most likely a pair of slip rings and brushes
which could also be the problem.
which could also be the problem.